HIV-1 DNA is detected in bone marrow populations containing CD4+ T cells but is not found in purified CD34+ hematopoietic progenitor cells in most patients on antiretroviral therapy

Abstract

Identifying cellular reservoirs of human immunodeficiency virus type 1 (HIV-1) in patients on antiretroviral therapy (ART) is critical to finding a cure for HIV-1. In addition to resting CD4(+) T cells, CD34(+) hematopoietic progenitor cells have been proposed as another reservoir. We obtained bone marrow aspirates from 11 patients on ART who had undetectable plasma HIV-1 RNA. HIV-1 DNA was detected in CD4(+) T cells from peripheral blood in all patients and from bone marrow cellular fractions containing T cells in most patients. We did not find HIV-1 DNA in highly purified CD34(+) populations using either a sensitive real-time polymerase chain reaction assay or a coculture assay for replication-competent HIV-1.

Figure 1.

Analysis of human immunodeficiency virus type 1 (HIV-1) DNA in CD34⁺ hematopoietic progenitor cells. A, Purification methods used. CD34⁺ cells were first enriched from bone marrow mononuclear cells (BMMCs) using anti-CD34–conjugated magnetic beads. Highly pure populations were then obtained by flow-cytometric cell sorting using anti-CD34 and anti-CD3 antibodies. B, Representative flow cytometric analysis corresponding to CD34⁺-enriched vs CD34⁺-sorted cell populations from (A); phycoerythrin (PE) and fluorescein isothiocyanate (FITC). C, HIV-1 DNA copies/100 000 cells in peripheral CD4⁺ T cells (CD4⁺), sorted CD34⁺ cells, bone marrow depleted of CD34⁺ cells (CD34-depleted), CD3⁺ cells sorted from enriched CD34⁺ cells (CD3⁺), unfractionated BMMCs, and peripheral blood mononuclear cells from uninfected donors (HIV-PBMCs). Each color square represents a different patient designated by BM (bone marrow) and study number. The corresponding color HIV- PBMCs are the negative controls for the specific patient experiment. For patient 1, only sorted CD34⁺ and CD34-depleted fractions were tested.